Presently, there is no effective and reliable system in place for the sending of communication signals along an electric fence line. It will be desirable however, to have such a system. For instance, if it was possible to send a trigger signal along an electric fence line from an electric fence energiser to an information station or responder, information could be sent back to the energiser. This information could include data on the status of the fence line in various places or maybe other useful parameters. These other parameters may not necessarily be associated with the electric fence itself and could perhaps be from a meteorological station or other information collecting and monitoring devices. Instead of a trigger signal, the electric fence energiser may send signals which operate machinery, such as opening or closing gates.
Security fence systems usually consist of a single series fence and therefore information about separate sectors within the security area cannot presently be readily accessed by sending communication signals along the electric fence line. With a device that can function as described above, separate fences can be used within a security system and information can be sent to and received from individual sectors within the whole of the security system. Furthermore, such a device can be useful to farmers who presently need to walk an entire farm to check if and where there are faults in their electric fence system.
Electric fence energisers have characteristics which are generally not found in other devices. For instance, electric fence energisers produce high voltage pulses at regular intervals--generally in the order of one second apart. To achieve this, an energy storage device such as a capacitor is discharged through a transformer. Standard communication means such as sending tone bursts and so forth are extremely difficult, if not impossible to electrically couple with transformers such as those used in electric fence systems. It is thought that a third winding on the energiser transformer would be required- which can be expensive and difficult to arrange. Another problem with electric fence systems is that the electric fence line or wire (transmission line) is extremely long and a signal used in standard communication means could be attenuated as it travels along the electric fence line.
As a general comment, it is very difficult to predict either mathematically or empirically if a pulse of a particular type will propagate satisfactorily along an electric fence line.